Fluid pressure reducing valve



W. w. SMI-TH FLUID PRESSURE REDucING vALv Jan. lz3,l 1940.

Filed Jan.l 6, 1958 U Il` n nanas J.

, UNITED vsrATi-:s

` num massima annuonra vALvn wmismmsmannm oranges.; application January s, ma, ses.: No. nissanl s cnam. y(ci. zarzn maintain a predetermined relationship betweenv 10 the reductions at the various stages.

A further object of the invention is to provide a multi-stage iluid pressure reducing valve of such character that by design the pressure drop eii'ected Yby each stage will be of such'value that l5 the velocity ofv ilow, for any'given iluid, from one stage to another will be below the value that.

would set up noise and vibration. and the pressure drop through one stage will always bear a.A definite relationship to the drop through any 20 other stage.

A still further object oi' the invention is to provide a ymultistage fluid pressure reducing valve that will in eect be like a plurality oi'. valves connectedl in series, i. e., the outlet oi' one con- 25 nected to the inlet of the'next,- etc., and provided with a common control means whereby the Iiiow areas oi' all the valves will always remain ilxed with respect to one another.

And a further object oi' the invention is'to proso vide a valve ot the character referred to above' v that shall `be operable in water, oil, steam and gas lines, and, in the case oi' steam lines, be

adaptable for desuperheating purposes. f

ther objects of the invention will, in part, be

as apparent and will, in part, be obvious from the following description taken in conjunction with the accompanying drawing in which:

Fig. 1 is a more or less diagrammatic view o! a valve embodying one i'orm of the invention, shown 'lo in connection with a steam line for reducing highy pressure steam to low pressure steam, means being illustrated for desuperheating the steam entering the low pressure line and controlling the temperature thereof, and for controlling the valve a to maintain the pressure oi' the low pressure steam constant at some prede ed value.

Fig. 2 is a view in section of the lower portion l of the valve shown in Fig. 1;

' 5o Fig.3isaviewinsectionof theupperportion of the valve shown in Fig. 1, Figs. I2 and 3 together representing'a view in section ot the en-` tire valve assembly; and l Figs. 4 to 8, inclusive, are views in section taken u on lines IV-IV to VIII-V111, inclusive, Fig.- 2,

showing the construction of the valve at the various pressure-reducing stages.

'Throughout the drawing and the speciiicaon like reference characters indicate like parts.

The pressure-reducing valve assembly illus- '5 trated in the drawing, comprises the valve proper I and the valve operating mechanism 2. The valve proper comprises a valve body 3, having a valve plug 4 therein for controlling the rlow of iluid through a plurality oi' pressure-reducing 10l stations or stages 5 to'9. inclusive, disposed in series.

The valve body is bored to receive a plurality l of annular members or rings I 0 to Il, inclusive,

disposed one on top oi' the other. The lowermost 15 annular member Aor ring I 4 rests on a shoulder I5 at'the bottom of the body bore and the upper ring is pressed downwardly by means of a packing ring I6 which is locked in .place by means of ring nut II having threaded engagement with the upper enlarged portion of the bore ofthe valve body. The upper end of the valve plug is provided with a plurality of grooves I9 in which packing material may be placed to render the upper end of the plug fluid tight.

Each annular ring, I0 to I4, inclusive, is formed at its lower end with an inwardly projecting ange 2i that embraces the valve plug I and has a sliding, -substantially pressure-tight iit therewith.

- The valve plug may be groovcd at the various in a predetermined manner so that the reduction in the pressure of the iluid is accomplished in steps of either equal or progressively increasing, or progressively decreasing values. As illustrated, the valve plug is designed so that the pressure reductions at the various stages are substantially equal. As shown, more particularly by Figs. 4 to 8, inclusive, the valve plug is provided 40 with one groove G5 ,at stage 5, two grooves at station l, three at station l, four at station 8, and ve at stations; and these Vgrooves are so yshapedl and pro "rtioned that the ow area of each stage will be such that the velocity of the uid ilowing through any one stage will be below thevalue at which noise and vibration occurs.n which velocity may be diilerent for diierenttypes of iluids o r-liquids.` In the case of steam, the

ilow areas should be so .proportioned that'the 60 v velocity throughv anyv stage-will not exceed approximately 1000 feet per second, for example. Thus, the stages beginning with stage 5 and ending with stage 9 are so proportioned that each onehasailowareathatwillkeeptheveiocityot u the fluid passing through it at a value below that which would develop noise and vibration. and at the same time establish substantially uniform pressure reduction at the various stages.

Fluid enters stage 5 of the valve through inlet 2l, passes through stages 5 to 8, inclusive, into the bottom of the bore in the valve body, thence through a side passage 24 into upwardly directed passages 25 and 28 to outlet 21. Passages 25 to 25 are employed to allow the outlet and inlet to be at the same level so that the valve may be connected into the line without .oisetting the high and low pressure sections thereof. Where this is not important, the outlet of the valve may as well be at 2i or 28, which when not used may be closed with screw plugs and 3|, respectively.

The upper ends of passages 25 and 26 may be connected to the space above ring nuts i1 through passages 82 (only one of which is indicated) to allow such iluid as leaks past the upper end o! plug 4 to escape into outlet 21.

In case the valve is to be used for reducing high pressure steam to low pressure steam, and it becomes necessary or desirable to desuperheat the steam, the valve may be provided with an inlet for water, and this inlet may be so located that the desuperheating water may be introduced into any one of the pressure-reducing stages of the valve. Such an inlet may be provided as at 8l that would introduce the water into one of the low pressure stages, say stage 8 for example, at which point the velocity of the steam would be high enough to atomize the water and thoroughly mix it with the steam. Ii desuperheating is notv required, this inlet may be closed with a screw plug such as indicated at 80 or 8|.

When the valve plug in the position shown in Fig. 2, the valve is osed, as the lower ends of all the now grooves G5 to G8, inclusive, are above valve iianges or seats 2| oi' the respective members Ill to Il, inclusive. As the plug is moved downwardly to a point where the lower ends of the grooves G5 to G8 are below seat 2|, ow through the valve may take place, the maximum iiow occurring when the centers of these grooves are opposite their cooperating valve seats or rings. For intermediate positions of the valve plug, the total flow area of the valve will -be correspondingly less and the flow through the valve correspondingly lower. By controlling the position o! valve plug l, the flow through the valve may be regulated as desired, and for every position oi the plug the pressure drops through the various stages will remain nxed and constant with respect to each other.

The valve operating mechanism 2 comprises a pressure actuated member, as for example a diaphragm 85 that is operatively connected by means oi' a thrust plate 88 and stems 81 to 88 to the upper end of valve plug 4.

Plate 88 is secured to, the upper end of rod 81 and the plate and diaphragm 85 are disposed within s. two-part housing 88, the edges of the diaphragm being clamped between the housing parts, thus providing .a 'pressure-tight space Il into which operating pressure is introduced through cn-inlet 4|. i

Housing Il is carried by a support column I2 that is' secured at its lower end by means of 8 clmping nut 48 toa bonnet M threaded into the upper end or valve body 3.1. Rod n posses through a stumng box in bonnet u comprising a lower packing ring Il, stumng box ring 4l, an upper pecking ring 41, a gland 4I and n a nut Il.

lValve plug I is urged toward its closed position by means of coaxial coil springs 5| and 52 disposed between a plate 58 and a plate 5l. Plate 58 rest on a thrust bearing 55 carried by an adjusting screw -58 that is threaded into a strut 51 5 formed integrally with column l2. The lower end o1' screw 58 is countersunk to accommodate bearing guide balls 58 for stem 81.

The upper ends ofvsprlngs 5| and 52 bear against plate 5l and the thrust on this plate is transmitted to plate 35 by means of a sleeve 50 disposed about stem 81 and passing through the lower part of housing 89. Downward movement of diaphragm is limited by a stop 8| carried on the inside of housing 28, and upward movement is limited by a stop 52 carried by plate 59. The lower part of housing 89 is recessed about Stem 31 to accommodate bearing guide balls 53 ior sleevel.

Fig. l illustrates diagrammatically the use 0f the pressure-reducing valve in reducing the pressure of iuid 'owing from a high pressure line 64 into a low pressure line 65. The high pressure line is connected to valve inlet 28 and the low pressure line is connected to outlet 21. Where l it is desired to maintain the pressure in the low pressure line substantially constant, a ,regulator 68 may be employed. This regulator responds to the pressure in line 55 and transmits a iluid pressure to space 40 of such value that valve plug l will be held in the position requiredy to allow suillclent flow of fluid into line 85 to maintain the pressure therein substantially constant at some predetermined value.

Regulator 88 comprises a pressure-responsive element 81, such as a bellows, disposed within a pressure-tight casing 88 to which pressure tromthe low pressure line is tra itted by means ot a pipe 58. The regulator icludes an escapement valve 1li which is Aoperated by the pressureresponsive bellows through a lever 1| Lever 1| is iulcrumed at one end as at 12 and is operatively connected to the bellows through a push rod 18. having a knife edge engagement at 15 with the lever. A spring 15 urges lever 1| in e direction opposite to that in which it tends to be moved by the bellows in response to increasing pressures.

The escapement valve comprises a valve body 15 having an exhaust port 11 that exhausts to lo the atmosphere, an inlet port 18 that is connected I, to -a pipe 1l supplied with operating iluid of substantially constant pressure and an outlet port l0 connectedby a pipe Il to inlet 4I oi' housing 88. The valve includes a movable member n l2 disposed within the valve body and which is provided with tapered surfaces 8l at its opposite ends disposed to cooperate with valve sects at the inlet and outlet ports of the valve body. The valve member is urged upwardly by means of a n spring 8l. When the valve member is seated on the seat of inlet port 18 the pressure in space ll oi' housing ll is at its minimum value as any, nuid medimn therein will exhaust to the atmosphere. When the valve member is in engagement with the seat or exhaust port `1'| the pressure in chamber 4I will be at a maximum and valve plug l will be-moved downwardly to its maximum open position.

when valve I2 occupies any intermediate podtion. depending upon the pressure acting on bellows 81, the pressure in chamber I5 will be of l some intermediate value. Thus. u valve 82 moves iirom oneseattothccthcrthcpnsmreinchsmberllwillhavoadeiinitevaluadgmdinguponl l in low pressure line l substantially constant -at any value of p pounds per square inch, regulator I8 will be adjusted to be in equilibrum with this pressure; if this pressure rises, the escapement valve wil be shifted to a positionyto lower the pressure in chamber 4I to a value that will vallow valve plug 4 'to move upwardly and thereby decrease the rate of ilow oi iluid from high pressure line 64 to low pressure line BI. If .the pressure tends to decrease in low pressure line '85, the regulator will act in the opposite direction and increase the pressure in chamber 4U so that the valve plug will be moved to a position that Will allow greater iiow to the low pressure line and thereby raise the pressure in that line.

If the pressure-reducing valve I is to be used in a steam line where high pressure steam is to be reduced to some predetermined value of low pressure steam, it may be necessary to introduce water into the steam to de superheat it, This may be accomplishedby introducing water into inlet 34, and if it is desired to maintain the degree of superheat in the low pressure line substantially constant, a temperature-responsive regulator 84 may be employed to operate a valve 8B that would in turn regulate the amount of water delivered from a supply line 86 into stage 8 of the reducing valve.

Valve 85 in such case could be operated by a pressure-responsive element 81, such as a bellows, operating against a spring IB which tends to urge the bellows upwardly, thereby urging the water regulating valve toward its open position. The tempera-ture responsive regulator 84 would respond to the temperature oi the steam in the low pressure line 85 and cause such a control pressure to be delivered to the bellows 81 that valve 85 will be in the position required to deliver the requisite amount oi' water to maintain the temperature oi the steam at the value for which temperature-responsive regulator 84 would be set.

. The temperature-responsive regulator I4 is illustrated diagrammatically' and comprises a temperature-responsive mechanism 89 having its Y thermal element extending into the steam line and having itsmovable element 80' connected to a lever 80' similar to lever 1I of regulator 66. The lever would operate an escapement valve 'I0' such as valve 'l0 of regulator 68. Since valve 'il' is similar to valve 10, corresponding parts are designated by the same reference characters primed. If the temperature of the steam increases above the desired predetermined value, regulator I4 operates to transmit a a decreased control pressure to the operating bellows 81 for valve 85, causing it tomove toward its open position, thereby increasing the rate of ilow oi' water into stage l oi' the'pressure-reducing valve. lIf the temperature decreases, indicating that too much water was being introduced into the low pressure steam, regulator 84 so operates valve 'il' that a higher operating pressure l will be delivered to bellows I1. With increased pressure, bellows Il will move valve 8l toward closed position, thereby decreasing the amount ci.' water introduced into the steam passing to the low pressure line.

'-It will be apparent 'from 'the above descriptionof the pressure-reducing valve `l-il, lthat this valve may be utilized in many ways and that muior-reducingmiidpressureandsteampresgrooved portion providing a flow area past its co- 'that the now area of each succeeding grooved boiler, valve plug 4 could be adjusted automatically in responsel to some function indicating the load on the boiler, as for example in accordance with variations in steam ilow from the boiler.

If the valve is used to control boiler blowdown, outlet 21 will be discharging to 'the atmosphere or into a ilash tank, but in either case the pressure at the outlet will be constant. In adapting the valve for -blowdown purposes, the difference between the boiler pressure and the atmosphere or discharge pressure is determined. From this the number oi' stages required is determined so that the drop through any one stage will bear a fixed relationship to any other stage.

From the above it will be seen that the multistage valve in eil'ect comprises a plurality oi valves connected in series. i. e., with the outlet of one valve connected to the inlet oithe next valve, etc., and a control means i'or1'all of them that controls the ilow varea. through'each simultaneously and in such fashion that the iiow area ci any one will bear a fixed relationship to any y, other for 'every position ofthe control means. 3f* Thus stages E to 9, inclusive, may be considered as individual valves, connected as above described and all controlled simultaneously by a control means such as plug 4.

Having Ithus described the'llinvention what I d@ claim and desire to secure by Letters Patent is:

l. A multistage fluid pressure-reducing valve comprising a valve body having a bore therein provided with a plurality oi' spaced valve seats, an inlet at one end oi the bore and `an outlet communicating with the other, said valve seats being coaxial, and a valve plug in said bore disposed to have a uid shut-ofi ilt with at least one of said seats when-in one position, the valve plug having spaced grooved portions, each grooved de portion extending lengthwise of the plug, such grooves being so spacedthat when the plug is in shut-ofi' position any grooved portion will lie between its adjacent pair of valve seats, each such operating valve seat when the plug -is moved out of shut-01'! position.

2. A multistage fluid pressure-reducing valve according to claim 1, characterized by the tact 00 portion of the valve plug, starting with the one adjacent to the inlet, is greater than the one immediately preceding the same.

3. A multistage iluid pressure-reducing valve according to claim 1, characterized by the fact that the valve is provided ,with another inlet positioned to communicate with the space between a pair oi valve seats remote from the inlet to the valve whereby another huid maybe introduced nimma 1:0 .comminsle wmf the suis v110mm: 'm

through the valve.

4. A multistage iluid pressure-reducing` valve according to claim 1, characterized-by the fact that the flow area of each succeeding groovedl portion oi the valveplug, with the one 7g 4 la wanttotnemietamtertnsntaone immediately preceding the same; and that the valve is provided with another inlet positioned to communicate with the space between a pair of 4 g valve seats remote from the inlet to the `valve whereby another iluid may be introduced thereinto to comminzle with the huid owins through the valve.

5. A valve according to claim 1 characterized u by the fact that each grooved portion following v the iirst pressure-reducing stage comprises a plurality oi' grooves spaced circumferentially of the plus. v

8. A uuid pressure-reducing valve comprising a jmunicate with the space between a pair of valve seats remote from the inlet whereby another fluid xay be introduced therewith to commingle with the uid passing through the valve.

WILLIAM W. SMITH. 

